Thermostat



Patented May 4,1943

UNITED STATES PATENT L orrics 2.318,4 wuum n. Grimm. gnfbor. N. r. Application June 3l. 1942, Serial No. 9,071 4`Clalms. (Cl- ZOO-14.)

Hy invention relates to improvements in thermostats and particularly to thermostats having means actuated upon a rapid rate in rise of tem. perature for controlling electric circuits adapted for operating alarm, signal and like devices.

Thermostats to which my invention is applied comprise a heat transmitting shell forming an air chamber, with one wall of the chamber in the form of a' flexible diaphragm adapted to be distended by the air in said chamber and close the circuit. upon a sudden rate in rise of temperature, in the event of a ilre within the sone where the thermostats are located, for protection against fire. 1

The object of my invention is to provide novel means for actuating the thermostat at a predetermined temperature in addition to the rate inrise of temperature actuating means.

A further object is to arrange a small quantity of volatile material ia communication with the air chamber of the thermostat; which material will become active at a predetermined temperature and expand the air in said chamber for distending the diaphragm land thereby controlling the circuit for actuating the alarm.

A further object is to locate a container within the air chamber of the thermostat for normally containing and sealing the volatile material and provide a seal for the container which willyield under pressure created by the volatilization ofthe material within the container.

A further object is to arrange the container for the volatile material so that the increased temperature of the atmosphere surrounding the air chamber will be readily conducted to the volatile material within the container.

A further object is to construct the shell formp ing the air chamber of the thermostat with means for readily detachlng the shell from the base for making the container which is located within the shell accessible for nlling the container and for inspection purposes.

'l'hese together with various other novel features of construction and arrangement of the parts, which will be more fully hereinafter described and claimed. constitute my invention.

Referring to the accomphylns drawing:

Pig. l is a central vertical sectional view of a thermostat embodying my invention.

Fig. 2 is a partial plan view of Fig. l.

In the drawing in which like reference-characters refer to like parts, l illustrates a thermo-A stat comprising a support. or body t, formed of insulating material. Said support is made in two sections l and l adapted for clamping a flexible metal diaphragm il between the sections by means of bolts Il.

Ihe base section l of the support is providedwith ears Il for fastening the device to a ceiling. A wall Il of the sectional 'I is positioned horizontally and in spaced relation to the diaphragm Il and forms an air space it, which communicates, through an aperture i'l in the wall Il, with a cavity il formed in the section 'I above the wall il, which cavity I. in turn communicates with theatmosphere through openings i! formed in the section 'I for the admission of electric conductors 2l and 2l of a circuit 2l, including a source of current u and a relay 2|, adapted for controlling an alarm circuit It. including a source of current 2l and signal devices. such as abellandalamp.

Aterminalplateilismounteduponthewail il by means of a rivet 2l. and said plate is provided with binding screws ll adapted for thc attachment of the conductor 2l. A metal plate 8| forms a conductor between the rivet 2l and the diaphragm il and 'electrically connects the latter with the conductor Il.

An adjustable contact screw 82 extends through the wall Il and is mounted in threaded engagement with a tubular rivet It, which latter is secured upon the wall il. A terminal plate u is also secured upon the wall 'il by the rivet 3l. and said plate is provided with binding screws 3l for the attachment of the conductor 2i.

The contact screw '82 is thuselectrlcally connected with the conductor il, sndis adapted to besecured in adjusted position upon the rivet I by means of the lock nut It. with the inner end of the screw normally in adjusted spaced relation with the diaphragm il, which latter il provided with a metal disk tl, which engages the screw 82. and insures the thin metal diaphragm against being puncturedl by enmement Vlwitlithe screw I2. Saiddlsk" also adds Ilifiicient weight to the diaphragm so that it will normally move away from the screw t! to form an air gap and open the circuit Il.

A thin metal hemispherical shell Il is mounted upon the clamp section I of the support and forms an air chamber il, with the diaphrlsm il forming a distendable wall of said chamber. The section s is rai-gleed with the usual slow leak' aperture Il, through which slow changes in the pressure of the air in the chamber Il may equalize with the atmosphere without moving the diaphragm. The section l is also provided witha'n aperture Il. for testing purposes. which aperture Il is normally closed by a plug Il, as

section 8.

described and claimed in an application for Thermostat filed by me December 12, 1941, Serial No.

chloride, or similar material which will volatilize i below a temperature of 165 degrees F.

The container 45 is normally sealed by a cork' A48, or other suitable sealing means, which will yield when the material 46 volatilizes and allow the gas generated within the container 45 -to enter the air chamber 39 and thereby subject the air in the latter to an increased pressure which will distend the diaphragm I into contact with the center Contact screw 32 and close the circuit 23, including the relay 25, which in turn controls the circuit 26. for actuating the alarm and signal devices 60 and 6l. y

. A'preferred form ofmy invention is shown in Fig. 1, and comprises the container 45 formed by a hemispherical partition, or wall 41, having its edge portion secured, by meansio solder 49 or other suitable means, to theinner surfacel of 'the-shell'38. .The container 45 is-formed by the thin metal wall 41v and a portion of the shell 38, which latter forms the lower enclosure of the container, so that heat will -be readilyconducted through the shell 38 to the volatile material 46 within the container. The wall 41 of the container is provided with a neck 50,forming an opening which is normally sealed by the'cork 48, whichV latter will be forcedput of the neck 50 when the material 46 volatilizes. I

The shell 38 is detachably mounted upon the w clamp section 8, so that the inner container may be readily accessible for filling and inspection purposes. The clamp section 8 is provided with a depending ange 52, having a screw thread 53 formed thereon, for the attachment of a screw thread 54, formed upon the shell 38. The

shell 38 is provided with a shoulder 55, upon which a gasket 56 is adapted to be positioned and clamped between said Vshoulder 55 and the end facing surface of the flange 52, thus forming an air seal. Y

'I'he topfacing surface of the clamp section 8 is tightly clampedagairist. the edge portion of the' diaphragm l0, by the 'bolts I2, and forms an air-tight seal between -the diaphragm and the An inwardly projecting ange 58, formed upon the section 8, provides a support for the iiexible diaphragm I0 and restricts its downward movement. The flange 58 is provided with an opening 59 through which the air under pressure in the chamber 39 acts upon the diaphragm.

The operation is as yfollows: In the event ofa nre causing a sudden increaseinthev temperature of the air surrounding the shell 38, the heat will be transmittedl through the thin metal shell 38 and subject the airin the chamber 38 to an increase in pressure -which will distend the diaphragm into contact with the screw 32 and close the circuit 23 and operate the signal devices IG f and 6 I. If the rate in rise of temperature is slow, the increasein the pressure, of theair in the chamber 39 may equalize with the-atmosphere,

diaphragm, in which event the heat from the nre will be conducted through the shell 38 to the volatile material 46, within the chamber 4l, which material will volatilize at a predetermined temperature and force the cork from the container 45.

The pressure generated by the volatilization of the material 46 will pass from the container 45 into the air chamber 39 and subject the air in the latter to an increase in pressure which will also move the diaphragm into contact with the screw 32 and complete the circuit 23'and operate the signal devices.

Various changes in the construction and arrangement of the parts may be made without de parting from my invention.

I claim:

1. A thermostat comprising an insulating sup port, a pair of terminals mounted thereon and adapted for connection in a circuit with a source of current supply, an air chamber mounted upon said-supporaa flexible diaphragm forming one wall of said air chamber normally positioned in spaced relation to one of said terminals and adapted to be distended to establish electrical connection between said terminals and close said circuit by pressure of the expanded air in said chamber against the diaphragm responsive to theA action of heat, a container infcommunication with said chamber, a seal normally closing communication between said container and said chamber, and volatile material in said container adapted to expand and break' said seal at a predetermined temperature and subject the air in said air chamber to an increase in pressure forl also distending the diaphragm to establish electrical connection between said terminals.

2. A thermostat comprising an insulating support, a pair of'terminals mounted thereon and adapted for connection in a circuit with a source of current supply, an air chamber mounted upon said support, a distendable diaphragm forming one wall of said air chamber and normally posi-V tioned in spaced relation to one of said terminals and adapted to be distended to establish electrical connection between said terminals and close said'circuit by pressure of the expanded air in said chamber against the diaphragm responsive to the action of heat, a container located within said chamber, said container having an aperture forming communication between said container and said chamber, a seal normally clos-- ing said aperture, and volatile material in said container adapted to expand and break said seal at a predetermined temperature and subject the air in said chamber to an increase in pressure for also distending the diaphragm to establish electrical connection between said terminals. Y

3. A thermostat comprising an insulating support, a pair of terminals mounted thereon and adapted to be connected in a circuit with a source of current supply, a thin metal shell mounted upon said support forming an air chamber, a distendable diaphragm forming one wall of said chamber and adapted to be distended to establish electrical connection between said terminals by pressureof the expanded air in said chamberagainst the diaphragm responsive to the action of heat, a wall having its/edge portion secured to the inner surfaceof said shelland forming a container within, the shell and separated from said air chamber by said wall,said wall having an apertureformed through the samecommul .nicating Iwith said chamber, means normally through the aperture 40, without moving the sealing said aperture, and volatile material in said container adapted to expand and break said seal at a predetermined temperature and subject the air in said chamber to an increase in pressure for also distending the diaphragm to establish electrical connection between said terminals.

4. A thermostat comprising an insulating support having a base section and a clamp section, a distendable diaphragm mounted between said sections, a pair of electrical terminals mounted upon the base section and adapted Ior connection in a circuit with a source of current supply` an annular ange upon said clamp section, a hemispherical metal shell, means detachably mounting the edge portion of the shell upon said Y flange, said shell forming an air chamber with the diaphragm forming one wall thereof, said diaphragm adapted to be distended to establish electrical connection between said terminals and close said circuit by pressure of expanded aix` in said chamber responsive to the action of heat, a partition wall having its periphery secured upon the inner surface of the shell and forming a receptacle within the latter, said partition wall having an aperture forming commu- .iication between the container and the air chamber, means normally sealing said aperture. 

